Post Office Protocol version 3 is a long-established way for email clients to download mail. Because it relies on legacy authentication and cannot handle multifactor authentication, organisations often block it with Conditional Access.
Also called Post Office Protocol version 3.
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In the Ultra Transcenders books
Each book explains POP3 in context, with comparison tables and the common traps.
Terms in this definition
- Legacy authentication
Older protocols, such as Exchange ActiveSync and legacy mail apps (the Other clients category), that sign in with basic authentication. MFA isn't possible with them, so Conditional Access policies use the client apps condition to block them.
- MFA
Multifactor authentication: asking for another factor on top of a password at sign-in, usually required by a Conditional Access grant control.
- Conditional Access
Policy engine in Microsoft Entra ID P1 that, depending on signals such as risk or named locations, allows access subject to controls like MFA or a compliant device, or blocks it.